The objective is to determine whether the enhanced rate of glucose utilization exhibited by virus-transformed mammalian cells is primarily due to an increased rate of glucose transport into the cell, or due to changes in the regulation of glucose metabolism within the cell. A second objective is to determine whether such enhancement of glucose transport and/or metabolism is specifically due to the presence in the transformed cell of the genome of a transforming virus, or whether the enhancement is a reflection of the overall growth rate of the cell. We are measuring the flux of the non-metabolizable glucose analog 2-deoxy-D-glucose into intracellular free sugar, and sugar-phosphate pools, respectively in (a) normal cells showing density dependent growth, (mouse 3T3 cells), (b) 3T3 cells that have been transformed by SV40 or Rous sarcoma virus, (c) 3T6 cells, a spontaneously transformed cell line, and (d) normal and transformed cell lines under conditions of serum deficiency and sufficiency. We seek to determine with certainty whether the increased flux of 2-deoxyglucose into intracellular phosphate pools of transformed cells is due primarily to increased transport, as has been reported by numerous other workers, or due not to increased transport, but to intracellular trapping as a result of increased phosphorylation subsequent to transport, reflecting enhanced glycolysis.